Multiple aperture die

ABSTRACT

Billet material is extruded through a die having a plurality of die apertures thereby to produce simultaneously a plurality of extruded products such as wire. In one embodiment, the die has a conical mouth with a first die aperture at the apex thereof and with a plurality of radially equispaced second die apertures located forwardly of the first die aperture, the second die apertures having bevelled entries at the inlet ends thereof communicating with the conical mouth. In another embodiment, the die has multiple aperture groupings arranged therein, each grouping having a central die aperture and a plurality of peripheral die apertures radially equispaced about the central die aperture.

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Schmidt, et al.

PROFILE, SUCH AS THE LIFT FORK OF A LIFTING DEVICE, AND METHOD OF MANUFACTURING SAME Inventors: Ernst Schmidt, Sven Lennart Ingestad, and Sven Ewert Lindell, all of Mjolby, Sweden Assignee: AB Pygg- OCH Transportekonomi (BT), S 161 11 Bromma, Sweden Filed: June 18, 1974 Appl. No.:480.5l5

Foreign Application Priority Data June 21, 1973 Sweden 73088155 U.S. 113/116 R; 214/750 Int. Cl. B21D 53/00 Field of Search 72/379: 113/116 R;

[451 Nov. 4, 1975 [56] References Cited UNITED STATES PATENT 3.6ll,965 lO/l97l Lange ll3/ll6 Primary Examiner-Lowell A. Larson Attorney. Agent. or Firm Flynn & Frishauf [57] ABSTRACT A starting sheet like material has a first peripheral portion bent to a suitable obtuse angle. for example 120, and then the same bent part is bent further to an acute angle, for example 45. A peripheral portion of the material adjacent the first bent portion is bent to an approximately right angle and the first bent portion is bent further in fully towards the underlying material of the starting sheet. Then, the previously bent peripheral portions and at least an additional part of the periphery of the profile are further bent at about a. right angle to arrive at a profile having a high degree of strength.

9 Claims, 3 Drawing Figures US. Patent Nov. 4, 1975 ET TB CT 2 To [T J N T1 '\1 F FIG/A mizzzl FIG/B FIG/C Sheet 1 of 3 The present invention is directed to a method of manufacturing profiles, especially steel profiles intended for the lift forks of lifting devices, by means of shaping the starting material in a series of defined, consecutive steps, and to the resulting profile.

Up to now have such profiles been built up by the welding together of several parts. This prior method is time-consuming, calls for great precision at the execution of the welding and is costly. The welded joints must be carefully inspected, as the stress and strain during functional operation of the part is considerable. A broken joint can cause serious mishaps.

The object of the present invention is to eliminate all these drawbacks while providing a method for manufacturing of lift forks which is considerably simplified and cheapened and adapted to mass production.

SUMMARY OF THE INVENTION According to the present invention, a method of manufacturing a profile from a starting sheet-like material comprises bending a first part of the starting material at its edge to a suitable obtuse angle, for example 120 (FIGS. 2A and 2C), to form one end of the intended profile; then bending further the same first part of the material bent in the first step to an acute angle, for example 45 (FIG. 3C); bending of an edge portion of the material farther away from said one end of the intended profile to an approximately right angle (FIG. 3D); then bending further the same first part of the material, now at the acute angle, in fully towards the underlying material (F IG. 4C); and then bending more of the material around at least an additional part of the periphery of the profile to form a completing, mainly right-angled edge (FIGS. 5A-5 D) to arrive at a profile having a high degree of strength.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. lA-lD show the starting materiaha sheet or plate of steel or other suitable material of appropriate form and thickness, possibly with one or several holes in the vicinity of its one end, Figs. lB-lD being cross-sections taken at B-B, C-C and D-D, respectively;

FIGS. 2A-2D show the material in the vicinity of said end after bending to an obtuse angle a, FIGS. ZB-ZD being cross-sections taken at B-B, C-C and D-D, respectively;

FIGS. 3A-3D show the material after bending to the angles b and 0, FIGS. BIB-3D being cross-sections taken at 5-8, C-C and D D, respectively;

FIGS. 4A-4D show the material after bending the portion at angle b in towards the underlying material, FIGS. 4B-4D being cross-sections taken at 8-8, C-C and D- D, respectively; and

FIGS. 5A-5D show the material after further material has been bent around substantially the whole periphery to an approximate right angle d, FIGS. 5B-5D being cross-sections taken at B-B, C-C and D- D, respectively.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT The present invention is described with reference to manufacture of a lift fork of a fork lift device, for example a lift fork for use in a fork lift device of the general type described in US. Ser. No. 332,177, filed Feb. I3, 1973, and assigned to the same assignee as the present application, and in Industrial Equipment News, September, 1971, page 59, Pallet Truck, the contents of which are incorporated herein by reference. The invention, however, can be used for making other steel profiles which may be similarly shaped and/or have similar structural requirements.

Referring to FIG. I, a sheet of starting material 1, preferably a steel sheet, illustrated which has a hole 2 therein. The starting sheet 1 may include more than one hole 2, or may have no holes therein, depending upon other design considerations. When the invention is used to fabricate a lift fork for a fork lift device, the hole 2 may be provided for access to rolling wheels provided at the forward end of the fork.

According to the present invention, the starting peripheral portions 3 and 4 of the material 1 are bent to an obtuse angle a, for example so as to provide a profile as shown in cross-section in FIG. 2C. The remaining portions of the starting sheet I are not bent in the first step.-

In the next step, as shown in FIGS. 3A-3D, the same portions 3 and 4 of the material which were bent in the first step (FIG. 2C) are now bent to an acute angle b, for example 45, as shown in FIG. 3C. During this second step, further peripheral portions 5 and 6 of the starting material 1 are bent to an approximately right angle 0 as shown in FIG. 3D. When the device being fabricated is a lift fork for a lifting device, the further portions 5 and 6 are remote from the free end thereof.

In the third step, as shown in FIG. 4C, the peripheral portions 3 and 4 of the material which were initially bent in the first step are now further bent fully in towards the underlying material of the starting material I. The portions 5 and 6 are not bent in this step.

Next, as shown in FIGS. 5A-5D, the peripheral portion resulting in the vicinity of the bent over portions 3 and 4 are further bent up to a substantially right angle (1 as illustrated in FIG. 5C. Likewise, the remainder of the peripheral portion of the starting material is bent to a substantially right angle a as shown in FIGS. 58 and 5D so as to provide a profile having the whole periphery thereof bent, except for the rear end of the profile which, in the case ofa fork lift truck, attaches to the lifting mechanism and is not required to be bent. In certain applications, however, it may be advantageous to bend the rear portion 9 of the underlying material I. As shown in FIG. 5B, the front bent over portions 7 and 8 are bent over at approximately right angles d, and as shown in FIG. 5 D the portion of the underlying material 1 adjacent the peripheral portions 5 and 6 are also bent over at approximately right angles cl so as to form a generally U-shaped structure, in cross-section, at the peripheral edges of the profile in the vicinity of the portions 5 and 6. The portions 3 and 4 have double bent over construction so as to enhance the structural strength of the resulting profile at these points. If necessary,

the double-bent over construction illustrated in FIG. 5C can be extended over a greater length of the resulting profile, depending upon strength requirements of the resulting item.

The resulting device, as illustrated in FIGS. 5A- 5D has remarkable strength and the manufacture thereof is considerably simplified and cheapened, thereby better adapting same to mass production. Further, since the construction is simple, fewer defects exist in the resulting item, thereby rendering the invention still more economical. Additionally, less skilled manufacturing personnel is required for producing devices according to the present invention as compared with the prior art Welding method.

As mentioned above, the present invention is particularly suitable for use in manufacturing lift forks for fork lift trucks.

While the invention has been described above in detail, various modifications and alterations can be made within the scope of the invention as defined in the amended claims. For example, all of the angles are approximate and depending upon materials, fabrication equipment and structural-strength requirements, the angles may be varied. Also, the lengths of the various peripheral portions bent in the various steps may be varied.

We claim:

1. Method for manufacturing profiles, such as steel profiles for the lift forks of lifting devices, from a sheet or platelike starting material comprising:

(a) bending at least a first peripheral edge portion of the starting material to an obtuse angle, said first peripheral edge portion being at one end of the intended profile;

(b) bending further said first peripheral edge portion of the material to an acute angle;

(c) bending at least a second peripheral edge portion of the starting material to approximately a right angle, said second peripheral edge portion being farther away from said one end of the intended profile;

(d) bending still further said twice bent first peripheral edge portion of the material fully in towards the underlying starting material; and then (e) bending more of the starting material around at least a further portion of the periphery of the profile, and further bending the starting material portions adjacent said previously bent first and second portions to approximately a right angle, to form a mainly right angled edge around at least substantially the whole periphery of said profile.

2. Method according to claim 1 wherein steps (b) and (c) are performed simultaneously.

3. Method according to claim 1 wherein said obtuse angle is approximately 4. Method according to claim 3 wherein said acute angle is approximately 45.

5. Method according to claim 1 wherein said acute angle is approximately 45.

6. Method according to claim 1 wherein said starting material is an elongated strip of material, said bending steps (a)(d) being carried out on opposed longitudinal peripheral edge portions of said strip.

7. Method according to claim 6 wherein opposed longitudinal peripheral edge portions are simultaneously bent during each respective bending step.

8. Method according to claim 1 wherein said starting material is a steel sheet or plate.

9. Method according to claim 1 wherein said first and second peripheral portions are adjacent to each other.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3 91 6 669 DATED November 4, 1 975 INVENTOR) I Ernst SCHMIDT et al It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading of the patent, change name of Assignee t0: --AB BYGG- OCH TRANSPORTEKONOMI (B'I).

Signed and Scaled this third D ay of February 1976 [SEAL] A ttes t:

RUTH C. MASON C. MARSHALL DANN Amsfing ff Commissioner oj'Patems and Trademarks UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3 91 6 669 DATED November 4, i975 INVENTOMS) I Ernst SCHMIDT et a1 it is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown beiow:

In the heading of the patent, change name of Assignee t0: -AB BYGG- OCH TRANSPORTEKONOMI (BT).

Signed and Stealecl this third Day Of February 1976 [SEAL] Attest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner ofPatents and Trademarks 

1. A die comprising: a. a die body having an entrance end; b. a plurality of die apertures extending through said die body; c. said die apertures being arranged in the form of groups, each group comprising a plurality of die apertures; d. a plurality of flared mouths, each flared mouth being associated with one of said groups and opening toward the entrance end of said die body; e. in each group of die apertures one of said die apertures is centered on the longitudinal axis of the flared mouth associated with said group.
 2. A die comprising: a. a die body having an entrance end; b. a plurality of die apertures extending through said die body; c. said die apertures being arranged in the form of groups, each group comprising a plurality of die apertures; d. a plurality of flared mouths, each flared mouth being associated with one of said groups and opening toward the entrance end of said die body; e. one of said groups is centered on the longitudinal axis of said die body, the others of said groups being radially spaced around the said centrally positioned groups.
 3. A die as in claim 2, wherein: f. in each group of die apertures, one of said die apertures is centered on the longitudinal axis of the flared mouth associated with said group.
 4. A die comprising: a. a die body having an inlet end and an outlet end; b. a first group of a plurality of die apertures extending through said die body, said group having an entrance end and an exit end and centered on the longitudinal axis of said die body; c. a first conical mouth extending from the inlet end of said die body to the entrance end of said first group, said first conical mouth opening from the entrance end of said first group toward the inlet end of said die body; d. a plurality of second groups of die apertures, each of said second groups comprising a plurality of die apertures and having an entrance end and an exit end, said second groups of die apertures being radially spaced around said first group of die apertures; e. a plurality of second conical mouths, each second conical mouth being associated with one of said second groups of die apertures, each second mouth extending from the entrance end of its respective second group and intersecting the first conical mouth, said second conical mouths opening forwardly from the entrance end of its respective second group.
 5. A die as in claim 4, wherein: f. in said first group of die apertures, one of said die apertures is centered on the longitudinal axis of the die body, and the other die apertures of said first group are radially spaced around said centered die aperture.
 6. A die as in claim 4, wherein: f. in each of said second groups of die apertures, one of said die apertures is centered on the longitudinal axis of the second conical mouth associated with said second group, and the other die apertures of said second groups are radially spaced around said centered die aperture.
 7. A die as in claim 6, wherein: g. in said first grouping of die apertures, one of said die apertures is centered on the longitudinal axis of the die body, and the other die apertures of said first group are radially spaced around said centered die aperture. 